"Voilà... the ZF1. It's light. Handle's adjustable for easy carrying, good for righties and lefties. Breaks down into four parts, undetectable by x-rays. Ideal for quick, discreet interventions. A word on fire power. Titanium recharger. 3000 round clip with bursts of 3 to 300, and with the replay button, another Zorg innovation, it's even easier. One shot, and replay sends every following shot to the same location."
- – Jean-Baptiste Emanuel Zorg, The Fifth Element
Flechette Blasters are a type of weapon used by Adeptus Mechanicus Skitarii. A very interesting weapon, it occupies its own unique little page as it is a specialised form of Galvanic Weapon. A lightweight but lethal firearm, it is the favoured tool of Sicarian Infiltrators. This silenced weapon fires hundreds of tiny darts, each of which bears a dormant cell awakened in the gun's chamber. Where one dart hits, it emits a homing beacon that attracts others, resulting in a series of impacts that burrow through bone.
Think of it like freezing water in a crack to break something bit by bit. The darts smash into the opening made or started by the first one, wedging more and more darts in to break open the target and the whole mess presses ever deeper.
In terms of tabletop, these nasty little pistols are available on the Infiltrators paired with a Taser Goad. It's got rather low strength at S3, but 5 (FIVE!) shots means it packs almost as much punch as a rapid-firing bolter, while being fireable in melee. Overall, it is a rather meh weapon that obviously suffers against enemy with decent armour. So stay clear from MEQs and above.
The Flechette Pistol is an interesting weapon by the sheer fact that it is not created by the Adeptus Mechanicus. Rather, it is a civilian-grade weapon made by the hive gangers of Necromunda (And more specifically, House Delaque, they really....really love these things).
Due to their origins, the Flechette Pistol is of inferior craftsmanship than the Flechette Blaster, even though the Flechette Pistol is a bigger weapon. True to its name, it fires a hail of flechette, however, it lacks the AdMech's homing feature found in the Blaster.
On tabletop, this is the signature pistol of House Delaque, the flechette is a reasonably priced rapid fire pistol with a gunshroud built in. Use the solid ammunition against rank and file, but make sure to switch to your toxin rounds when taking down champions and leaders.
The Flechette Carbine is the Flechette Blaster's bigger brother. Longer and more streamlined than their handheld cousins, the Flechette Carbine offers superior range and handling. These rifles are the primary weapon of the Pteraxii Skystalkers, who use these weapons to snipe enemy commanders in the air.
On the tabletop, the Flechette Carbines are essentially a death with a thousand cuts. With a 24" range, the Flechette Carbines are an Assault 5, S3, AP0, D1 weapon; it ain't a anti-tank weapon as its primary function is reducing light infantry like Termagaunts into Tyranid mince pie. For anti-armor purposes, the Skystalkers are instead, armed with a cluster of Arc Grenades which metaphorically shits their enemies to death.